Du, Pengfei; Qi, Rui; Zhang, Yafeng; Gu, Qingqing; Qu, Xiaoyan; Tan, Yuanlong; Liu, Xiaoyan; Wang, Aiqin; Zhu, Beien; Yang, Bing; Zhang, Tao

CHEM

2022, 8, 2451-9294

Du, Pengfei; Qi, Rui; Zhang, Yafeng; Gu, Qingqing; Qu, Xiaoyan; Tan, Yuanlong; Liu, Xiaoyan; Wang, Aiqin; Zhu, Beien; Yang, Bing; Zhang, Tao

Single-atom catalysts (SACs) are featured as an emerging type of heterogeneous catalysts due to their distinct reaction mechanisms. Beyond the conventional understanding, here, we report a dual effect of Pd-1-FeOx SACs in real reactions boosting reverse water -gas shift (rWGS) reactivity. Besides providing single active sites, Pd SAs surprisingly promote the dynamic carburization of FeOx surface over a long-term reaction, leading to outstanding rWGS activity (42.0 mmol(CO)$g(cat)(-1)$h(-1)) and CO selectivity (> 98%) beyond that of other reported Fe-based catalysts. Utilizing state-of-the-art characterization techniques, we reveal that this dynamic carburization yields a highly active Fe5C2 phase with the lowest activation barrier of 27.7 kJ/mol for the atmospheric rWGS reaction. The dual effect of SACs results in catalytic performance superior to that of Pd nanoparticles, over which carburization is inhibited by a rapid FeOx encapsulation. This work reveals the multiple roles of single atoms in real reactions, indicating the wider application of SACs.